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Topic: Cat C-7 Overheating- AGAIN (Read 1596 times)

I know this has been discussed repeatedly, but please bear with me. I know the basics. The motorhome is a 2006 Fleetwood Expedition with a Cat C-7, 300 HP, rear radiator. I purchased it new (special ordered) and have had it since 5-05. Full timed in it for 10 years. It now has 114,000 miles. I have had intermittent overheating problems. I have tried to keep the radiator/CAC clean, but as we know, that isn't easy. In Nov, 2010 (58,000 miles) I removed the radiator/CAC myself for cleaning. At that time I found quite a bit of debris on the front of the radiator. The CAC was actually pretty clean, so my cleaning efforts paid off to some extent.For the last year or so I have been having increasing overheating problems. I do run heavy a lot of the time, so that doesn't help. GCWR is 38,000, and I am often at 37,000+. Also, I am now based in Arizona, so hot weather is common. I replaced the regulators earlier this summer, since that is relatively easy, and I previously had a bad regulator. No help with the overheating this time. I decided I would have to pull the radiator/CAC again. I just got them out and again found the CAC pretty clean. There is a circle in the center, about 6" diameter with some blockage. The radiator has less debris than in 2010, perhaps 15% blockage. The blockage is mostly in the center, and just a bit on the extreme right and left sides. The water pump belt is slightly looser than I would like, but probably not enough to slip. I wish I had thought to check the belt tension earlier!

All hoses have been replaced recently. I plan to replace both belts, while it is easy. The fan bearing was replaced in 2010, but I don't like the feel of it now, so will replace it again. Same for the water pump tensioner. The serpentine idler and tensioner feel fine. Water pump and alternator feel fine.

So, for my questions:

1. Is it worth it to take the radiator to a shop for internal cleaning? I have always changed the coolant as needed or sooner, and have only use distilled water. I have been using Cat ELC for the last 5 years. I also did a cooling system flush with the Cat cleaner and distilled water when I changed over to ELC. A little online research makes me think that the chances of internal blockage are minimal.2. Is there any big trick to replacing the fan bearing? I do have a hydraulic press, but not a lot of tooling for it. The dealer charged me an hours labor before to install the new bearing in the housing.3. I have fairly easy access to the top of the fan shroud from inside the motorhome. I am thinking about cutting a couple of holes in the top of the shroud, perhaps 3" diameter. They would be at roughly the 11:00 and 1:00 positions, and would be between the fan and CAC. I wondered if anyone has tried this? These holes would allw much better access for cleaning.I know that I would need to seal the holes for operation. Considering that my CAC is staying pretty clean, I am not sure it is worth the effort. 4. Any other suggestions on the overheating issue? Anything else I should check/replace while I am in this far?

Boundertom, yes I live in western AZ. 20 miles from Blythe. cal. Again I do have Cat ETwhere I can readout what is going on with engine. As far as cutting into radiator shroud itwould compound the heating problem , my suggestion would not do this it there for a veryImportant reason. Few questions you are talking extreme heating at what temperatures areyou running on flat and climbing grades. Second question how much coolant is being lost ?When you replaced thermostat did you get the new style with/out the jiggle pin on the edge.Last question in replacement of thermostat or regular as correct term Cat uses if it did have a jiggle pin it requires a correct position it has to be set into housing. There are some thingsthat might be overlooked. I feel your problem is not severe and just triggering what is called a logged event code but it getting where you want it to go away and I understand. Last question What is the intake manifold temperature running on flat and on grades, than oil pressure reading durning the heating event. Have you thought transmission temperature with pulling heavy load may be having input into the problem . There are many things involved here topin point location of heating. Ask Dave, Dave Atherton Retired Cat Mechanic

Thanks for the response, Dave. I live in the Wickenburg area. As for temps, on level ground, temps stay at 190 to 195. This is even in 90+ temps and with heavy load. On any incline, the temps rise quickly. 215 is common, and I have gone as high as 230. Yes, I gear down and try to keep RPMs at 2000 to 2100 on grades, as that seems like it works best for pulling and cooling. Transmission temps run somewhat lower than coolant temps, but I understand that transmission heat adds to the cooling load. I do not lose any coolant. I am not sure about intake manifold temperature. I am not aware of the significance of that. I do have a Scan Gauge, and usually have it showing the Intake Air temp. Is that what you are referring to? If so, I would say it usually runs 10 to 20 degrees above ambient. I admit to not watching that closely when I am having a heating issue.

As for cutting into the shroud, that would only be for cleaning purposes. I would seal any holes for operation. I understand that airflow through the radiator/ CAC must be maintained. Since the CAC is staying pretty clean, I am not sure this is worth it anyway. The debris I have is mostly on the front side of the radiator.

I can't say about the new regulators, RE: jiggle pin. I bought them from a large Freightliner dealer in the Phoenix area (You might guess where). It is a high volume operation, so I would ASSUME their stock is fresh. I was not aware of there being a correct position going into the housing. If this is important, it would be fairly easy for me to check at this time, while coolant is drained and everything is apart. I just remembered, I bought an extra pair of regulators and gasket, so I could look at those. Perhaps you could elaborate on the "jiggle pin" and correct positioning. At any rate, I notice no difference in temperatures after replacing the regulators

I just got the radiator and CAC out yesterday. I will clean them thoroughly with Simple Green Extreme. I would appreciate your thoughts on taking the radiator to a shop for cleaning. I am leaning toward it probably not being worthwhile. I am also thinking of replacing the water pump, while it is relatively easy to access, since the MH is 13 years old and at 114,000 miles. Hoses very recently replaced. Will replace both belts, fan bearing and water pump tensioner bearing.

Thanks for your advice. It is much appreciated! If you are offering to put your equipment on my engine for testing, I would be grateful. I would be happy to come to your location after I get this rig back together.

boundertom, thanks for information on your heating problem, this gives me direction onWhere we are going with your problem. First of all I live in Quartzsite so we are not far away. Getting into your problem, first of all get a thermostat regulator from a Caterpillar Dealer for your Cat C-7 that is the new update without the jiggle pin. Second what information youreturned to me, you have what is called ( logged event code ). What this means you havesomething happening that comes and goes, but code is not a active fault Code which is good.First of all your temperature regulators opens at 191 deg f and is full open at 208 deg f. Yeson grades heat indicator will show hot but will cool right down going down the grade. NextVery important ( you have no coolant loss ), if your engine has extreme heating of whichInformation provided in your first post logged active fault Code would be present along with extreme coolant loss, you do not but might be possible faulty heat indicator presenting faultyTemperature readings triggering warning light and derate of engine rpm. Again would suggestreplacement parts Caterpillar only not aftermarket parts there claim to be the same as Catparts but there not. Ask Dave, Dave Atherton Retired Cat Mechanic

OK, I have updates. First, the regulators are Cat #115-4223. They do have the "jiggle pin". Can you explain the significance of the jiggle pin? The radiator and CAC had more blockage than I first realized. Simple Green Extreme, water hose, and air pressure (carefully applied) were having little effect. I decided to take them to a radiator shop. We decided to replace the radiator with a new one. They were to clean and leak test the CAC. They determined that the CAC had a pretty significant amount of leakage. I had already had this sealed with epoxy 8 years ago. The shop said there wasn't anything they could do since it was already epoxied. So, I am getting a new CAC also. If the CAC was leaking as bad as they say, that would also be contributing to my overheating troubles. I decided to go ahead and replace the water pump and alternator. I am also replacing the serpentine tensioner and idler. I replaced the bearings in the fan hub and water pump tensioner. So all belt driven parts have been replaced, except the AC compressor. I don't want to go there. So, right now I am waiting for some of these new parts to arrive, which should be in the next 3 days. Will hopefully get it together this weekend. Altogether, I will be into this for nearly $3,000. Not cheap, but the labor was free! And I shouldn't have to worry about any of these items for quite a few years.

Boundertom, your temperature regulator you have bought of which I did mention in earlier post is the old style regulator and not the new style temperature regulatorwhich removed the jiggle pin because of problems. What does many temperature regulators do not get changed out at 2 -3 years maintance and jiggle pin breaks offand engine temperature does not reach correct cooling temperature ( like running with loose radiator cap ). My suggestion leave it in now you have it installed and lateron change out to the new style update temperature regulator. Ask Dave, Dave Atherton Retired Cat Mechanic

Question. Are you changing out your alternator and water pump just because you have the radiator out or is something wrong with them? How long does these two items normally last?Mine are 11 years old,should I be thinking of changing them out?

Basically, if you have to PAY RETAIL for labor, AND they are fair with charges, if components are over a decade old, probably makes sense to replace them as labor charge should be minimal once there is complete access to the engine.

Captpar, Brett is correct the point is that they are there and cost to change out major component Is very good business. The old saying if not broke don’t fix it but figure today’s labor cost it isextremely cost effective to change out major cost items like you have done so. Ask Dave, Dave Atherton Retired Cat Mechanic

Question. Are you changing out your alternator and water pump just because you have the radiator out or is something wrong with them? How long does these two items normally last?Mine are 11 years old,should I be thinking of changing them out?

There is nothing wrong with the alternator, or water pump. Likewise, nothing wrong with the fan bearing, or idler pulleys. The motorhome has 114,000 miles and is 13.5 years old. Access to many of these components is difficult with the radiator in place. It is all pretty simple now. I do all of my own work, and have an aversion to being broken down. That almost never happens, as I try to take excellent care of my equipment. My motorhome has been in a shop exactly one time. That was for a repair under warranty, which was actually a pretty simple repair. I have heard and read of all of these components breaking or wearing out in much less time and mileage than I have accrued. Sometimes with disastrous or at least expensive consequences. Likewise, I am sure that many of these components last considerably longer. It is a matter of comfort level, I guess. I have the ability to do the work, but I prefer to do it in the comfort of my own garage, rather than on the side of the road. I am sure a lot of people think it is foolish to replace still functional parts. And, MOST people probably wait until a part fails to replace it. I am not saying that is wrong, but it may not be economical or convenient.

Whether YOU should replace your water pump or alternator is not something I am able to advise on, other than to explain my rationale.

I don't think there is any set rule on when to replace components with a few exceptions. I have replaced water pumps and alternators with as little as 1000 hours and 35,000 miles and there is a lot of equipment out there with countless hours and miles on those components so I think it comes down to the circumstances involved. It your digging in to get to take care of one problem and the cost saved to replace a few common fail components is sensible but not a guarantee that you wouldn't have to go in to replace again a short time down the road.

Gentleman we all have good points on components replacement or not to replace untilComponents fail. There are many of motorhome people carry extra parts with just incase of failure. The down side to all of this how can we replace failed part on the road.Another way to look at this picture, removing radiator and charged air cooler for serviceand at that time replace fan belts , water pump, idler pulley, fan bearings etc. keep the old parts for spares being they still work but lot of hours of operations. Owner can relaxand still carry the parts removed . Many ways to look at cases like this and again myselfFew extra dollars now at labor paid to remove radiator and charge air cooler person canrelax on the road being towed to unknown service and start over removing components you just had off 5 months ago. Ask Dave, Dave Atherton Retired Cat Mechanic

I wanted to provide an update. I got the motorhome all back together about a week ago. The new radiator is copper/brass, as opposed to the aluminum/plastic OEM radiator. I did not weigh it, but it is definitely heavier. Reinstalling the radiator/CAC assembly was all that two of us could handle. (We aren't kids). IF I have to do this again down the road, I will probably try to figure out some rigging to lift it with my engine hoist. Anyway, it is all together, and NO LEAKS! That is always a worry to me, when so many things have been disconnected. I took it our for a short test run and all is good. Low ambient temperature, no hills, and no 10,000 pound trailer, so I don't know about overheating, but I am confident that we will be good now. We leave for FL in about 12 days, but we are only towing the CR-V this trip, so it won't be much of a test on the overheating. But, like I said, I am confident it will be good.